body {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background-color: #f0f0f0; /* 背景颜色 */
    margin: 0;
    flex-direction: column;
}

.meter {
    position: relative;
    width: 300px;
    height: 300px;
    margin-bottom: 20px;
}

.meter-background {
    background: url('meter-background.png') no-repeat center; /* 背景图像 */
    background-size: cover;
    width: 100%;
    height: 100%;
    position: relative;
}

.meter-needle {
    position: absolute;
    width: 2px;
    height: 150px;
    background: black;
    top: 50%;
    left: 50%;
    transform-origin: bottom; /* 旋转中心在底部 */
    transform: rotate(0deg);
}

.knob-container {
    position: relative;
    margin-top: 20px;
    width: 150px;
    height: 150px;
}

.knob {
    position: relative;
    width: 100%;
    height: 100%;
}

.knob img {
    width: 100%;
    height: 100%;
    transform: rotate(0deg); /* 初始旋转角度 */
    transition: transform 0.1s; /* 旋转平滑过渡效果 */
}
